Speaker
Description
We investigates non-thermal leptogenesis from inflaton decays in the minimal extension of the canonical type-I seesaw model, where a complex singlet scalar $\phi$ is introduced to generate the Majorana masses of right-handed neutrinos (RHNs) and to play the role of inflaton. We systematically study non-thermal leptogenesis with the least model dependence. We give a general classification of the parameter space and find four characteristic limits by carefully examining the interplay between inflaton decay into RHNs and the decay of RHNs into the standard-model particles. We find that the strongly non-thermal RHNs scenario occupies a large parameter space, including the oscillation-preferred $K$ range, and works well for a relatively-low reheating temperature $T^{}_{\rm RH} \geq 10^3~{\rm GeV}$, extending the lower bound on the RHN mass to $2\times 10^{7}~{\rm GeV}$.
We demonstrate that such a unified picture for inflation, neutrino masses, and baryon number asymmetry can be realized by either a Coleman-Weinberg potential or a natural inflation potential for the inflaton. We find that non-thermal leptogenesis from inflaton decay offers a testable framework for the early Universe. The model-independent investigation of non-thermal leptogenesis should be useful in exploring this direction.
| Paper info | 2311.05824, accepted for publication in JHEP |
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